EL CEIBAL, GUATEMALA—New radiocarbon dates from the ancient Maya city of Ceibal suggest the origins of Maya civilization were both older and more complicated than previously thought. In the past, archaeologists have theorized that the influence of the older Olmec civilization was the major factor in the rise of Maya city states, while others held that the Maya developed their civilization independently. Now a team led by the University of Arizona's Takeshi Inomata suggests the answer is somewhere in the middle. The archaeologists have discovered a ceremonial platform at Ceibal dating to around 1000 B.C., about two hundred years before the Olmec built similar structures at the city of La Venta. At the same time, the team says they have evidence that the rise of Maya civilization was part of a broad cultural shift throughout Mesoamerica, and not an independent phenomenon.